Fabric clamp drive for automatically controlled short seam sewing machines



. E. WIDER' 3,425,287 FABRIC CLAMP DRIVE FOR AUTOMATICALLY CONTROLLED SHORT SEAM SEWING MACHINES Filed Dec. 15, 1966 Sheet of 2 In L ' w z 36 I3 3 7 .INVENTOR 3 ,EBERHARD un DER Feb. 4. 1969 I 5 Miam 3,425 2 7 FABRIC CLAMP DRI VE FR AUTOM T CALLY CONTROLLED SHORT SEAM SEWING CHINES Filed D90. 15, 1966 Sheet g of 2 TL 0 .4 IB/ 29 3 22 27 J V J INVENTOR EBERHARD LUlDER United States Patent 3,425,287 FABRIC CLAMP DRIVE FOR AUTOMATI- CALLY CONTROLLED SHORT SEAM SEWING MACHINES Eberhard Wider, Leongert, near Stuttgart, Germany, as-

signor to Union Special Maschinenfabrik, G.m.b.H., Stuttgart, Germany Filed Dec. 15, 1966, Ser. No. 602,034 Claims priority, application Germany, Dec. 15, 1965,

US. Cl. 74119 16 Claims Int. Cl. F16h 29/08; Db 3/04 ABSTRACT OF THE DISCLOSURE This invention relates in general to reversible mechanical driving apparatus and more specifically to apparatus for driving the cloth clamp of automatically controlled short seam sewing machines wherein the driving motion imparted to such cloth clamp is effective, in either driving direction, over substantially the whole period of the stitch i'orming cycle wherein the needle is disposed above the thread.

At the present time it is common to provide short seam sewing machines, such as buttonhole sewing machines or tacking machines, with a one-way drive wherein the direction in which the cloth clamp is driven is selectively reversible. It is common to use, in such a drive, a one-way wedging roller overrunning clutch which is effective to transmit rotational movement imparted thereto in one direction and inefiective to transmit rotational movement imparted thereto in the reverse direction. The direction in which such a wedging roller overrunning clutch is effective is, of course, dependent upon the position of the wedging elements or rollers within the clutch and a reversal of the effective direction of such a clutch is obtained by repositioning such rollers with respect to the remaining elements of the clutch.

In the case of short seam sewing machines having such a one-way reversible wedging roller overrunning clutch or other one-way drive means it has been, of course, necessary to provide both forward and reverse driving movement to the cloth clamp during the approximate 180 portion of the sewing cycle during which the needle is disposed above the cloth. Further, in utilization of oneway drives in sewing machines of the type herein considered it has been the practice merely to reverse the driving direction of the clutch such that that portion of the motion imparted to the clutch which originally was transmitted therethrough became, upon reversal, the nontransmitted motion and that motion which originally was not transmitted through the clutch became, upon reversal, the transmitted motion. Such a reversal of the clutch transmitted motion or driving stroke and non-transmitted motion or idle stroke, previously utilized, had the necessary eifect that the driving stroke in forward and reverse directions were eifected during different portions of the over-all stitch forming cycle or sewing cycle. That is, a driving stroke in the reverse direction occupied that porice tion of the sewing cycle which corresponded to the idle stroke in the forward direction.

In reversible one-way cloth clamp drives of the aforementioned type the etfective driving stroke in either the forward or reverse direction has been limited to an approximate portion of the total stitch forming cycle. Such a limitation upon the period of time allowable for the cloth clamp driving function has been necessitated by the need to drive the cloth clamp only during the approximate portion of the stitch forming cycle during which the needle is disposed above the cloth and, further, by the fact that the driving stroke in the forward direction could only be effected during a portion of the stitch forming cycle different from the portion allotted to the driving stroke in the reverse direction. Thus, the first 90 portion of the total 180 portion wherein the needle is above the cloth has been provided with the driving of the cloth clamp in one direction while the remainder of this 180 portion of the cycle has been utilized to provide cloth clamp movement in the opposite direction. The cloth feeding action so provided has been limited, in one direction to that portion of the stitch forming cycle wherein the needle is moving upwardly away from the cloth, while the cloth feeding action in the opposite direction has taken place only during that portion wherein the needle is moving downwardly toward the cloth.

In short seam sewing machines of the type set forth hereinabove, the necessity to utilize difierent portions of the stitch forming cycle, then, has invariably resulted in abrupt movements in both the cloth clamp driving apparatus and the portions of the sewing machine driven by such apparatus. Such abrupt movements require undesirable accelerations and retardations which lead to an overthrown or overrunning condition in the driven parts of the driving mechanism and in the driven parts of the cloth clamp which is operatively connected with the driving mechanism. Further, such abrupt movements, resulting in extreme accelerations and retardations, have a marked detrimental effect on the quietness of operation of the sewing machine.

In view of the foregoing, it is a primary object of this invention to provide, in short seam sewing machines, a cloth clamp driving apparatus wherein the driving movement imparted to the cloth clamp results in a smoother and quieter operation of the sewing machine.

Another object of this invention is to provide apparatus for driving the cloth clamp of automatically controlled short seam sewing machines including clutch means for selectively transmitting rotational motion in either of two directions and driving means for providing input motion to the clutch means wherein the driving means includes means for selectively phase shifting the movement imparted to the clutch means relative to the movement of the remainder of the driving means.

Still another object of this invention is to provide apparatus for driving the clutch clamp of automatically controlled short seam sewing machines including clutch means, driving means for providing input motion to the clutch means and phase shifting means for selectively phase shifting the movement imparted to the clutch means by the driving means through 180 relative to the movement of the remainder of the driving means.

A further object of this invention is to provide apparatus for driving the cloth clamp of automatically controlled short Seam sewing machines including clutch means capable of selectively transmitting rotational motion in either of two preselected directions, driving means for providing input motion to the clutch means, phase shifting means for phase shifting the movement imparted to the clutch means and control means for controlling both the phase shift of the phase shifting means and the Y direction of motion transmission by the clutch means.

Yet another object of this invention is to provide cloth clamp driving apparatus including a wedging roller overrunning clutch, drive means for providing input motion to the clutch and phase shifting means for selectively phase shifting the movement imparted to the clutch relative to the movement of the remainder of the driving means.

It is a still further object of this invention to provide cloth clamp driving apparatus for automatically controlled short seam sewing machines including clutch means for selectively transmitting rotational motion in either of two directions, driving means for providing input motion to the clutch and phase shifting means in the driving means including rotatably mounted slide rod means having a sliding member mounted thereon wherein rotation of the slide rod means results in a phase shifting of the movement imparted to the clutch relative to the movement of the remainder of the driving means.

-It is yet another object of this invention to provide apparatus for driving cloth clamps of automatically controlled short seam sewing machines including clutch means for selectively transmitting rotational motion in either of two directions and driving means connected to the clutch means for providing input motion thereto, wherein the driving means comprises a crank drive connected to slide rod means which is rotatably mounted and operatively connected to the clutch means to provide a phase shift of the movement imparted to the clutch with respect to the movement of the remainder of the driving means upon rotation of the slide rod means.

In the drawings:

FIGURE =1 is a side elevational view showing a buttonhole sewing machine suitable for employment in accordance with this invention.

FIGURE 2 is an enlarged fragmentary sectional view taken along the line 22 in FIGURE 1 showing a portion of the driving mechanism for the cloth clamp including the phase shifting means and reversible one-way clutch.

FIGURE 3 is an enlarged vertical cross section taken along the line 3-3 in FIGURE 1 and showing a portion of the cloth clamp driving apparatus including the phase shifting device and a wedging roller overrunning clutch.

FIGURE 4 is a diagrammatic representation of the cloth clamp driving apparatus.

Referring now to the drawings in detail, it will be seen that there is illustrated in FIGURE 1 a buttonhole sewing machine having a frame 1, a needle 2 attached to a needle bar 3 which is adapted to be driven in vertical reciprocal motion with respect to the frame 1. The buttonhole sewing machine of FIGURE 1 further includes a fabric clamp 4 suitable to clamp the fabric to be sewn in position and to shift such fabric in relation to the needle 2. A knife 5 is provided in a well known manner for slitting the fabric. It is to be realized that while FIGURE 1 shows a buttonhole sewing machine, the cloth clamp drive which forms the substance of this invention is equally applicable to any of the sewing machines generally termed short seam sewing machines.

The fabric clamp 4 may be connected in the customary manner to a driving nut (not shown). Such a driving nut is customarily mounted in threaded engagement upon a rotatable driving shaft 6 such that rotation of the driving shaft imparts a shifting movement to the clamp 4. The driving shaft 6 (best seen in FIGURES 2 and 3) terminates in a wedging roller overrunning clutch 7. The wedging roller overrunning clutch 7 may be formed in accordance with the known construction of such devices such that a number of wedging rollers or wedging elements 8 are disposed adjacent depressions (unnumbered) formed in the outer casing of the clutch. A roller cage 9 is provided to position the wedging rollers or elements with respect to the remaining operative elements of the clutch such that transmission of rotational motion in either of the two possible directions depends upon the positioning of the wedging rollers or elements 8 at either end of their respective depressions. The position of the rollers or elements 8 within the clutch is adjustable due to the connection of cage 9 to a shiftable element 11 (best seen in FIGURE 2). A shifting of the shiftable element 11 toward or away from the clutch 7 results in the rotation of cage 9 such that the wedging elements or rollers are driven into their wedged position at a selected end of the depressions adjacent each roller. The imparting of rotational movement to cage 9 via shiftable element 11 may be effected through any of a number of mechanical relationships between shiftable element '11 and cage 9 such as, for example, the provision of cooperating camming surfaces.

Shifting movement is imparted to shiftable element 11 via a control rod 14 and interconnections discussed more fully hereinafter. The rod 14 is suitable for cooperation with any of a number of known programmed control devices such as the well known control cam which is widely used in programming and controlling the course of an entire sewing operation.

The driving apparatus seen in FIGURES 2 and 3 is provided by a primary driving shaft 19 on which is disposed a gear 18 in engagement with a gear 17 mounted upon a secondary driving shaft 16 in driving engagement therewith. The secondary driving shaft 16 terminates in a crank 15. Mounted upon the crank 15 is a pitman arm 21 which is operatively connected to the phase shifting device which will be more fully described hereinbelow.

Articulately journaled about the secondary driving shaft 16, upon a bushing 28, is a clutch driving lever 26. The clutch driving lever 26 is connected to the exterior of the wedging roller overrunning clutch via a connecting link 29. Pivotal movement of the lever 26 about shaft 16 and bushing 28 results in the imparting of oscillatory motion to the input of clutch 7.

The phase shifting portion of the cloth clamp driving apparatus comprises a pair of slidable rods 23 which are slidably mounted in a housing 24. The housing 24 is rotatably journaled in the sewing machine frame 1 by a pair of bushing elements 31 and 32 such that rotation of the housing 24 results in a redisposition of the sliding rods 23. Connected between sliding rods 23 is a connecting stud 22 to which the aforementioned pitman arm is connected. Thus, the crank 15 is capable of providing, through the pitman arm, a sliding movement to the sliding arms 23. The direction of such sliding movement is, of course, dependent upon the rotational disposition of housing 24 with respect to the sewing machine frame 1.

A slotted slide element 25 is disposed upon the stud 22 in guiding relation to the lever 26. Movement of the stud 22 resultant from the sliding of slide rods 23 provides a pivotal movement to the lever 26 through the slotted slide element 25.

The housing 24 has aflixed thereto a stud 33 upon which is mounted a connecting rod 34. Movement of connecting rod 34 imparts to housing 24 via the stud 33 a rotational movement. Connecting rod 34 is adjustably secured to a slotted member 35 by means of a guide slot formed therein. Slotted member 35 is connected to an arm 12 to form a control lever, generally referred to by the numeral 13 which, in turn, is connected to the control rod 14. Thus, movement of the control rod 14 results in a rotation of the housing 24 of the phase shifting device. The control rod 14 further operates through the arm 12 pivotally mounted upon pivot stud 36 to shift element 11 with respect to clutch 7. Members 35, and 12, then, provide a bellcrank lever such that upon movement of the control rod 14, the members 35, 12 and the lever, formed thereof, 13 rotate, to a limited degree, about a fulcrum provided by pivot stud 36.

In operation, rotational motion is provided to the driving apparatus by primary shaft 19 and is transmitted through gears 17 and 18 to secondary shaft 16 upon which is located crank member 15. Pitman arm 21 connecting crank member 15 with connecting stud 22 imparts a sliding motion to the portion of the phase shifting device comprising slide rods 23 and connecting stud 22. The slide block or slide element 25 positioned upon connecting stud 22 and within the slot 27 as best seen in FIGURE 4 imparts to the articulated lever 26 an oscillatory motion resultant from the angular disposition of the slide rods 23 with respect to the lever 26. The lever 26, in turn, provides the oscillatory motion as an input to the reversible one-way clutch mechanism 7 via the connecting links 29 and the casing of the clutch 7. The oscillatory motion of the lever 26, the connecting links 29 and the casing of the clutch 7 are illustrated by the unnumbered arrows associated with each of those members in FIGURES 3 and 4.

The reversible one-way clutch mechanism or wedging roller overrunning clutch 7 discriminates between the direction imparted thereto by lever 26 to provide an intermittent, one-way rotational movement to driving shaft 6. The unidirectional output of the overrunning clutch is analogous to that of a stepping ratchet and in FIGURE 4 the clutch has been so illustrated inasmuch as FIGURE 4 is a diagrammatic illustration intended to indicate the functioning of the apparatus. The step-by-step rotational movement of driving shaft 6 is converted to step-by-step linear movement of the cloth clamping apparatus by means of the well known driving nut in threaded engagement with the driving shaft 6.

A reversal of the direction of feed of the cloth clamping apparatus is effected by rotation of housing 24 such that the inclination of slide rods 23 is altered with respect to the general direction of movement of the crank drive formed by crank element 15 and pitman arm 21. This rotation of the housing 24 occurs upon movement of the control rod 14 as indicated by the unnumbered arrow associated with the rod 14 in FIGURE 2. The control rod 14, through its connection with the control lever 13, at the arm 12, pivots the lever 13 about the fulcrum provided by the stud 36 and thus pivots the slotted member 35, driving the connecting rod 34 as indicated in FIG- URES 2 and 4. The connecting rod 34 is connected with the housing 24 at the stud 33 as shown in FIGURES 2, 3 and 4. It will be noted that the phase shifting operation performed by the phase shifting device upon a rotation of housing 24 results in a 180 phase shift or reversal of movement of the motion imparted to clutch 7 via the pivotally mounted lever 26. Further, rotation of housing 24 such that slide rods 23 lie parallel to lever 26 results in the elimination of oscillatory motion of lever 26 and, accordingly, no motion is imparted to the cloth clamping portion of the short seam sewing machine.

It will be noted that control rod 14 acts through lever 13 formed by members 12 and 35 to simultaneously alter the rotational disposition of slide rods 23 and the disposition of wedging elements or rollers 8. That is, movement of the control rod 14 to effect pivoting of the control lever 13 and its slotted member 35 about the fulcrum provided 'by the stud 36 as discussed above, also effects pivoting of the arm 12 of the bellcrank lever 13 about this fulcrum as illustrated in FIGURES 3 and 4. The arm 12, through its connection with the shiftable element 11, shifts that element to move the roller cage 9 as discussed above, changing the position of the rollers with respect to the associated depressions in the casing of the clutch 7. Thus, upon reversal of the effective direction of motion transmission by clutch 7, a 180 phase shift is effected in the input to clutch 7 with respect to the remainder of the driving apparatus.

Utilization of this arrangement results in a drive mechanism for the cloth clamp capable of making use of the full approximate 180 portion of the stitch forming cycle wherein the needle is disposed above the fabric. The motion imparted to the clutch is characteristically sinusoidal and is a harmonic of the fundamental sewing cycle. This, then, results in an elimination of undesirable abruptness of movement and extreme accelerations and retardations which have heretofore had the af0rementi0n ed detrimental effect upon the operation of such sewing machines.

It will be readily understood that the hereinabove described cloth clamp driving apparatus is but one embodiment of the invention and that minor variations may be made in the manner embodied herein.

I claim:

1. Apparatus for driving the clutch clamp of automatically controlled short seam sewing machines comprising clutch means for selectively transmitting rotational motion in either of two directions, and driving means connected to said clutch means for providing input motion thereto including phase shifting means for selectively phase shifting the input movement imparted to said clutch relative to the movement of the remainder of said driving means.

2. Apparatus according to claim 1, wherein said phase shift means further defines means for phase shifting the movement imparted to said clutch means through relative to the movement of the remainder of the driving means.

3. Apparatus according to claim 1 further comprising phase shift control means for controlling said phase shifting means and clutch control means coupled to said phase shift control means for determining the direction of transmission of said clutch means.

4. Apparatus according to claim 3 wherein said clutch means comprises a wedging roller overrunning clutch.

5. Apparatus according to claim 3 wherein said driving means comprises crank drive means drivingly connected to said phase shifting means for imparting oscillatory movement to said clutch.

'6. Apparatus according to claim 5 wherein said phase shifting means comprises rotatable support means, slide rod means mounted on said support means, sliding means mounted on said slide rod means and operatively connected to said clutch means for imparting movement to said clutch means, said crank drive means being connected to said slide rod means and said support means being effective when rotated to change the disposition of change the disposition of said slider rod means relative to said crank drive means.

7. Apparatus according to claim 6 wherein said driving means further comprises a driving lever operatively connected to said clutch means to impart input movement thereto, said driving lever having a slot formed therein, said sliding means being disposed in said slot to impart oscillatory movement to said driving lever.

8. Apparatus according to claim 7 wherein said driving lever is pivotally mounted at one of its ends, a connecting link connected to said driving lever at its other end, said connecting link being connected to said clutch means.

9. Apparatus according to claim 6 wherein said driving means further comprises a driving lever operatively connected to said clutch means to impart input movement thereto, said slide rod means comprising two slide rods and connecting means connecting said rods, said sliding means, crank drive means and driving lever being connected to said connecting means.

10. Apparatus according to claim 4 wherein said wedging roller overrunning clutch includes a shiftable roller cage operative todetermine the transmitting direction of said clutch means, said clutch control means being operatively connected to said shiftable roller cage to shift the same.

11. Apparatus according to claim 10 wherein said phase shifting means comprises slide rod means and r0- tatable support means mounting said slide rod means for changing the angular disposition of said slide rod means, said phase shift control means being operatively connected to said rotatable support means for rotation of the same.

12. Apparatus according to claim 11 further including multi-armed lever means and a control rod connected thereto for pivotally moving said multi-armed lever means, said phase shift control means including one arm of said multi-armed lever means operatively connected to said rotatable support means for rotating the same, said clutch control means including a further arm of said multi-armed lever operatively connected with said shiftable roller cage for shifting the same.

13. Apparatus according to claim 12 wherein said one arm having a guide slot formed therein, said slot adjustably securing said connecting rod to said second arm.

14. Apparatus for driving the cloth clamp of a sewing machine comprising input drive means for providing continuous input rotary motion in one direction to said apparatus, means for converting the continuous input rotary motion to intermittent rotary output motion including selectively operable means for reversing the direction of said intermittent rotary output motion and phase-shifting means in addition to and connected with said selectively operable means, said phase-shifting means comprising means for selectively changing the time relation of the motion derived therefrom ,with respect to the motion applied thereto.

15. Apparatus according to claim 14 wherein said phase-shifting means comprises means, interconnecting said means for providing input rotary motion and said means for reversing the direction, for changing said input rotary motion to oscillatory motion and for phase-shifting said oscillatory motion 180 with respect to said input rotary motion.

16. Apparatus according to claim 14 further comprising means for controlling both said means for reversing the direction and said phase-shifting means to simultaneously effect reversal and phase-shifting upon actuation of said means for controlling.

References Cited UNITED STATES PATENTS 714,284 11/1902 Dahl et a1. 11273 2,384,044 9/ 1945 Poorman 19251 2,845,807 8/1958 Harless 1925l XR 3,147,633 9/1964 Kelchner 74-142 3,294,208 12/1966 Anderson 19244 H. HAMPTON HUNTER, Primary Examiner.

US. Cl. X.R.

Patent No. 3,425,287

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION February 4, 1969 Eberhard Wider It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line 8, "clutch" should read cloth line 41, cancel "change the disposition of; same line 41,

"slider" should read slide Signed and sealed this 7th day of April 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Attesting Officer Commissioner of Patents 

